One of the problems with dry etch processes for via and trench features is the variation in the etch profile during the processing of a full lot of wafers. This may be due to the build-up of carbon (C) and fluorine (F) (collectively referred to as CF)-based etch gas constituents used for passivation and etch selectivity, which are used to form specific etch profiles for patterned wafers in semiconductor processing. If these constituents are not effectively removed from the chamber to the same degree during dry clean cycles between wafers, polymer deposition can accumulate in a chamber leading to the build-up of a film layer which can lead to particle formation and peeling, and can generate defects and device failure on a wafer. In addition, ineffective or inconsistent waferless dry cleaning (WLDC) of the chamber between device wafers, can lead to varying residual CF constituents in the chamber, which subsequently are introduced during a successive dry etch process of a device wafer that affects the uniformity of etch profile characteristics from one wafer lot to the next. The wafers making up a lot.